In the field of the production of hydrocarbons, after the operations for recovering hydrocarbons by means of the natural pressure of the underground formation containing hydrocarbons, a so-called “primary” recovery; then it is generally proceeded with so-called “secondary” recovery by injection of water. Within this context, it is generally necessary to treat two types of aqueous flows, i.e. water withdrawn from the environment and which is intended to be injected (at least initially) into the underground formation, and production water, which represents the aqueous fraction recovered in the production wells. This production water may be discarded into the environment or preferably re-used as injection water from the moment that it is obtained in a sufficient amount.
Both of these aqueous flows have relatively different characteristics as regards their content of various contaminants and notably of solid materials and hydrocarbons. Therefore, these aqueous flows are treated in a different way, causing multiplication of the pieces of equipment which is particularly undesirable in congested environments, notably at sea. Therefore there exists a real need of developing a method for treating water within the scope of enhanced oil recovery which is both efficient and simpler to be implemented, in particular, with a reduced number of pieces of equipment.